Most cores upon which pressure-sensitive tapes are wound are cylindrical in shape and are formed in a single, unitary, piece. The cylindrical tape core defines a cavity that is often useful for grasping the tape by the hand when unwinding for use. In addition, tape typically can be unwound from such cylindrical cores in an efficient manner and without creating creases in the tape. As is known in the art, creases in pressure-sensitive adhesive tapes will result in areas where the adhesive will typically be picked off in time and the tape will become non-adhering along the crease.
Typically, these cylindrical cores will be placed on a winding mandrel and pressure-sensitive tapes, such as masking or duct tape, will be wound onto the outer surface of the cylinder as the winding mandrel rotates. A number of these cores will usually be placed on the mandrel so that more than one roll of tape may be obtained at a time.
Generally, a wide sheet of pressure-sensitive tape will first be formed and then provided to a slitting machine for cutting the tape into narrower widths that are commercially acceptable for individual rolls. After the tape is slit, the tape is then provided to the tape cores mounted on the winding mandrel and the tape is wound thereon as the mandrel rotates.
Typical tapes that are wound on cylindrical cores are usually bulky and not compact. Most tapes wound onto typical cores are not sufficiently compact to place in the pocket of one's clothing or to fit into a confined space. Obviously, smaller rolls of tape may be formed that are compact, but many of these are still wound onto a cylindrically-shaped core. For example, most adhesive electrical tape is sufficiently compact to place in one's pocket. However, electrical tape is normally provided on a cylindrical core.
In response to the need for a compact roll of tape, the prior art has developed a pressure-sensitive tape core that is sufficiently small and compact so that it will fit into spaces that other commercial available tape rolls will not. In particular, the core for this prior art tape roll is shown in FIGS. 1 and 2. The prior art tape core 1 is in the form of an elongated rectilinear block having rounded ends 8. The shape of this prior art core 1 is defined by a half 2 having an upper flat, or planar, surface and half 3 having a lower flat, or planar, situated between two rounded ends 8. These two separate plastic halves 2 and 3 are connected at rounded ends 8 and define a generally symmetrical cavity 9 therebetween. This prior art core 1 is generally symmetrical in that, viewed from the side, the core has a top half that is horizontal, or planar, and a bottom half that is horizontal, or planar.
As shown in FIG. 2, the two halves 2 and 3 which form the prior art tape core 1 are not connected until they are snapped together on the winding mandrel. The two halves 2 and 3 are held together through a stud/aperture connecter system. Each half has two studs 4 and 5 projecting from one enlarged end of the half and two mating holes, or apertures, 6 and 7 defined by the other enlarged end of the half. Thus, when placed together, the studs 4 and 5 projecting from one enlarged end of a half will mate with the apertures 6 and 7 on the other enlarged end of the other half portion so that the halves 2 and 3 can be positioned together to form prior art tape core 1. The ends of the core are then taped to securely fasten the halves together prior to winding tape onto the core. Because the two halves 2 and 3 are identical and have both of the studs 4 and 5 on one end of the half and both of the apertures 6 and 7 on the other end of the half, the halves 2 and 3 must be aligned properly when mounting on the mandrel. In other words, one cannot properly mount the core onto the mandrel if the halves are positioned so that the studs 4 and 5 on one half are aligned with the studs 4 and 5 on the other half. The result of such a misalignment would be that the studs would abut one another and the apertures would abut one another. Thus, in order to mount this prior art core onto the mandrel, the core halves 2 and 3 must be properly aligned prior to mounting.
In addition, in this prior art core, there is no mechanism by which the core is held tightly on the mandrel. The mandrel used to wind tape onto these cores is in a rectangular blocked shape, with outer planar winding surfaces. The cavity formed between the two halves of this prior art core is symmetrical in that the distance between the top inner surface and the bottom inner surface that defines the cavity is constant throughout the length of the core between rounded ends 8. The rectangular-shaped, flat cores of the prior art devices have a tendency to slide off of and not be tightly held on the blocked-shaped mandrel.
In addition, this completely symmetrical design of the prior art device often hampers unwinding of tape by the consumer. Due to the fact that the outer winding surfaces of the core are planar, the tape generally unwinds in lengthwise sections, with the length defined by the distance between rounded ends. Thus, when unwinding tape from around the circumference of the core, the unwind is slightly hampered.
Thus, there exists a need for a compact tape core that can be securely mounted on a mandrel for winding tape onto the core. In addition, there is a need for a compact tape core that prealigns itself to increase manufacturing efficiencies when mounting the core onto the mandrel. In addition, there exists a need to improve upon the unwind characteristics of a tape wound onto a compact tape core.